Parking meters, gasoline pumps, cash-dispensers and similar machines are often provided with devices which print information on a receipt and feed the receipt to the customer who keeps it as a verification of the service or the article he has bought.
It is well known that these printing and feeding devices will sometimes get out of order, often owing to the fact that the customer either tries to remove the receipt from the device before it has been printed and separated from a slip or blocks the outlet opening of the device. Attempts to remove the receipt during the printing operation or during the separation may damage the printing device and the separation device which lead to it either that these devices cannot be used before having been repaired or that the receipt will be defective or illegible. Blocking the outlet opening of the device may lead to it that the receipt will get caught in the device and prevents the feeding of additional receipts or may lead to it that the device will be damaged.
If the printing and feeding devices are out of order the subsequent customer will not get the service or article he has bought or he will not get a correct receipt or will not get a receipt at all. Moreover, the devices must be repaired.